The present invention relates to a current supply circuit, a current supply device, a voltage supply circuit, a voltage supply device, an electro-optical device, and an electronic apparatus.
In recent years, a device that has an organic light emitting diode (hereinafter, referred to as an OLED element) has attracted considerable attention as an electro-optical device instead of a liquid crystal display device. The OLED element has an electrical operating feature of a diode and an optical operating feature of emitting light at the time of a forward bias, allowing luminance to be increased with an increase in a forward bias current.
An electro-optical device in which the OLED elements are arranged in a matrix has a plurality of scanning lines and a plurality of data lines, and pixel circuits are provided at intersections between the scanning lines and the data lines. Each pixel circuit has a thin film transistor (TFT) for supplying a current to each OLED element. A gray scale signal corresponding to a display gray scale level is supplied from a data line driving circuit to the data lines. In this case, a plurality of driving modules may constitute the data line driving circuit.
In such an electro-optical device, since the variation between currents flowing through the OLED elements occurs due to a difference in transistor properties between driving modules, it is difficult for a display device to emit light with uniform luminance. As a technique for improving the variance between the driving modules, there has been known a method of providing a circuit for generating a reference current and of using the reference current between a plurality of driving modules in common (for example, see Patent Document 1).
In addition, there has also been disclosed a method of separately providing a dummy digital-to-analog (DA) converter from a D/A converter for supplying a current to the data lines to be driven, and of using the current output from the dummy D/A converter as a common reference current between the plurality of driving modules (for example, see Patent Document 2).
In addition, there has also been disclosed a method of adding currents output from two adjacent D/A converters at the boundaries between the driving modules to drive the targets (for example, see Patent Document 3).
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2002-202823.
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2003-288045.
[Patent Document 3] Japanese Unexamined Patent Application Publication No. 2001-42821.